How selective soldering works
From: Author:Mark Hardy Publish time:2021-08-31 16:25 Clicks:0
How selective soldering works
Selective soldering acts on the underside of the board without affecting anything on the top. A board is positioned in a frame, and all subsequent operations occur automatically according to the process control system programmed in advance for that board.
For each solder point, the machine operator controls the flux, preheat dwell time, and solder position, reducing any side effect of other joints on the board, unlike a wave process, which swipes the entire board without discrimination. All process steps are independently done, one at a time, over the entire board population:
- All selective areas are fluxed first
- All areas are then preheated to activate the flux
- Each joint is soldered one at a time according to the program
In addition to a single point, selective can be designed to perform “dips” and “drags.” These are closely spaced joints that can be handled by the same soldering operation either by covering multiple points in a single dip, or by swiping a row of joints in a long connector, for instance, by dragging the solder tip across them.
